Portable hot tub for land and water

ABSTRACT

An easy to assemble portable floating hot tub for use in even cold and turbulent water includes an inflatable pontoon, an insulated liner peripherally connected to the pontoon and defining hot tub fill volume, and flexible members extending from the pontoon under the liner such that the weight of the liner filled with water is supported partly by the flexible members. A floor made of rigid spaced apart and parallel slats can be rolled up with the flexible liner and deflated pontoon. A collapsible frame made of connected rigid members may be provided in or outside of the liner. The pontoon is placed on the body of water and inflated. Filling the internal volume defined by the insulated liner with water causes it to descend below the pontoon. A portable heater having a heating capacity of at least 30,000 BTUs rapidly heats up the water within the hot tub. The system components can be transported in carry bags of less than 100 pounds and deployed by one person in an extremely small space, such as on a boat.

RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119 to U.S.Provisional Application No. 61/191,968, filed Sep. 15, 2008, and is alsoa continuation-in-part of U.S. patent application Ser. No. 12/072,438,filed Feb. 26, 2008, which claims priority under 35 U.S.C. §119 to U.S.Provisional Application No. 60/903,567, filed Mar. 27, 2007.

FIELD OF THE INVENTION

The present invention relates to a portable hot tub that floats in abody of water and, in particular, to an easily and rapidly deployable,portable floating hot tub that can be used in bodies of water that areturbulent and cold.

BACKGROUND OF THE INVENTION

Hot tubs or spas are excellent ways for relaxing and rejuvenating, aswell as therapeutically soothing sore muscles and body parts. Theconventional hot tub is mounted in or above the ground, has rigidsidewalls, typically a molded fiberglass shell for containing water, anda relatively sophisticated and expensive electronically monitored andcontrolled water heating system relatively permanently connected anexisting water supply system. Hot tubs are often combined with standardswimming pools, either close to but spaced from the pool or immediatelyadjacent thereto separated by a low dividing wall. The ability to switchback and forth from the cold pool water to the hot spa water isextremely exhilarating.

To date, there has not been an economically feasible portable hot tubfor use in remote locations away from the backyard. One difficult hurdlein constructing a portable hot tub is the necessity of providingextremely strong sidewalls to contain the large amount of water therein.Of course providing sturdy sidewalls increases the size and weight ofthe device which hinders portability. One possible answer to thispractical problem is to immerse the hot tub in a larger body of water,which equilibrates the hydraulic forces across the spa wall andtherefore reduces the structural strength requirements.

Several designs for floating hot tubs, spas and pools are known,including U.S. Pat. Nos. 4,126,905, 4,135,256, 4,754,502, 5,470,480,6,795,983, and 7,032,258. For a number of reasons, these designs lackone or more of the following: easy portability, easy and rapid setup,stability in turbulent water, or economic practicality. Some relativelyrecent floating hot tubs, such as in U.S. Pat. No. 6,795,983,commercially available as the HOT POD floating spa, are primarilydesigned for use in a pool with relatively flexible and lightweightconstruction, which makes them ill-suited for use in very cold andturbulent water. Indeed, the '983 patent promotes the ability to easilydepress the hot tub upper rim to facilitate entry and exit of bothpeople and surrounding ambient water. Hot tubs have been built intolarger boats, including crew ships and luxury yachts. Though technically“floating,” these hot tubs are not portable by themselves, and arerelatively permanently structurally installed and connected to theelectrical and water systems of the boat.

Consequently, there remains a need for a floating hot tub that isportable, easy and quick to set up by one person, stable in roughwaters, and within the budget of ordinary consumers.

SUMMARY OF THE INVENTION

The present invention relates to a hot tub that is portable and may beplaced in a body of water such as a pool, a lake, river or the ocean. Aprimary application is to use the hot tub behind a boat. Boaters inparticular would appreciate the ability to quickly deploy a hot tub inthe water behind their boat wherever they are moored.

This present application presents various portable hot tub designs thatcan be set on land or can float in a body of water. The elements of thetub are an inflatable pontoon, a liner, a thermal insulating materialattached to or incorporated in the liner, and optionally a slat floor orsome other rigidifying structure at the bottom of the liner.Additionally, the tub may use ropes or straps that extend from thepontoon under the floor of the liner, or attached to the rigidifyingslats

In one aspect, the present application provides a portable hot tub,comprising an inflatable pontoon arranged around a central aperture andan insulated flexible liner having an upper periphery secured to thepontoon around the central aperture. The flexible liner defines forms athree-dimensional shape to extend downward within the central apertureand form a hot tub fill volume. Flexible members extend from the pontoonto support a bottom of the liner such that when the pontoon is floatingthe weight of the liner filled with water is supported partly by theflexible members. A hand-carried portable heater having an inlet and anoutlet and hoses connected therewith circulates water to and from thehot tub fill volume. Desirably, the heater has a tilt sensor that shutsoff operation of the heater if the heater tilts more than apredetermined amount from an upright orientation.

The aforementioned hot tub may also include a floor of a more rigidmaterial than the flexible liner incorporated within a bottom surface ofthe liner and attached to the pontoon via the flexible members. Thefloor may be at least one lightweight panel of a flexible and strongmaterial, or a plurality of slats spaced apart and oriented in parallelsuch that the floor can be rolled up about an axis parallel to theslats. Preferably, the flexible members attach to anchors provided onthe pontoon. The upper periphery of the flexible liner may be secured tothe pontoon with a plurality of flexible members, or along asubstantially continuous interface.

Another embodiment of the present application is a floating portable hottub, comprising an inflatable pontoon arranged around a centralaperture, and an insulated flexible liner having an upper peripherysecured to the pontoon around the central aperture and defining athree-dimensional shape to extend downward within the central apertureand form a hot tub fill volume. A plurality of rigid members areincorporated in the bottom of the three-dimensional shape defined by theflexible liner. The rigid members have a deployed configuration definingat least a floor under the liner and a collapsed configuration tofacilitate portability. A plurality of flexible members extend downwardfrom the pontoon to support the bottom of the flexible liner and rigidmembers such that when the pontoon is floating in a body of water andthe hot tub fill volume is filled with water the weight of the linerfilled with water, and any occupants of the hot tub, is supported partlyby the rigid members.

The hot tub desirably features a hand-carried portable heater having aninlet and an outlet and hoses connected therewith for circulating waterto and from the hot tub fill volume. In one embodiment, the plurality ofrigid members defines part of a three-dimensional frame that attachesaround the exterior of the liner. In an alternative embodiment, thefloor comprises a plurality of slats spaced apart and oriented inparallel such that the floor can be rolled up about an axis parallel tothe slats. The upper periphery of the flexible liner may be secured tothe pontoon with a plurality of flexible straps attached to anchors, oralong a substantially continuous interface.

A still further embodiment described herein is floating portable hot tubcomprising:

-   -   an inflatable pontoon arranged around a central aperture;    -   an insulated flexible liner having an upper periphery secured to        the pontoon around the central aperture and having a        three-dimensional shape to extend downward within the central        aperture and define a hot tub fill volume;    -   a plurality of slats spaced apart and oriented in parallel into        a bottom of the three-dimensional shape defined by the flexible        liner, the slats having a deployed configuration forming a        reinforced floor of the liner and a collapsed configuration        wherein the slats are rolled up about an axis parallel to the        slats to facilitate portability;    -   a plurality of flexible members extending from the pontoon to        attach to the slats such that when the pontoon is floating in a        body of water and the hot tub fill volume is filled with water        the weight of the liner filled with water is supported partly by        the slats; and    -   a hand-carried portable heater for circulating water to and from        the fill volume.

The upper periphery of the flexible liner is preferably secured to thepontoon along a substantially continuous interface, such as by adhesiveor heat sealing. Desirably, open-ended pockets formed in an underside ofthe liner receive the plurality of slats. Furthermore, each slat mayhave at least one flexible member attached to both ends thereof. In oneconfiguration, there are two flexible members attached to each slat endextending upward in a V-shape to different anchors provided on thepontoon.

In another aspect, the present application provides a portable floatinghot tub that is easy to assemble and take down and can be used inenvironments with extremely cold and turbulent water. The hot tubincludes an inflatable pontoon that forms a buoyant ring, an insulatedliner peripherally connected to the pontoon and defining athree-dimensional hot tub fill volume, and flexible members that extendfrom the pontoon under a bottom of the liner such that when the pontoonis floating, the weight of the liner filled with water is supportedpartly by the flexible members. The hot tub may have a floor made ofrigid slats that are spaced apart and parallel and that can be rolled upwith the flexible liner and deflated pontoon for ease of portability. Acollapsible frame made of connected rigid members may be provided in oroutside of the liner. The pontoon is placed on the body of water andinflated. Filling the internal volume defined by the insulated linerwith water causes it to descend below the pontoon. A portable heaterhaving a heating capacity of at least 30,000 BTUs rapidly heats up thewater within the hot tub. The system components can be transported incarry bags of less than 100 pounds and deployed in an extremely smallspace, such as on a boat.

In general, the present invention provides a hot tub that is portable,easily assembled, easy to enter and exit, provides for comfortableseating, and can be used in environments where there is cold andturbulent water. The hot tub has a collapsible, rigid frame that makesit operable in turbulent water such as in a river or on the ocean. Wallsof the hot tub are constructed from a thermally insulating material sothat it retains heat and can be operated in cold water environmentsfound in lakes, rivers and oceans. The hot tub is portable and can becarried and assembled easily by a single individual in confinedenvironments such as on a boat or on the dock. Finally, the rigid framestructure of the tub provides for comfortable seating.

In one embodiment, the hot tub is constructed from three independentcomponents: a pontoon, a frame and walls. The hot tub is supported inthe water by a floating inflatable pontoon. The pontoon can beconstructed from one or more bladder units. The pontoon must be largeenough to stabilize the tub when people enter or leave the tub. Thesupport frame of the tub is made with structural materials such as pipesor rods, or any other structural material that may be easilydisassembled. The frame may include provisions for seating of one ormore people in the hot tub. Extra material may be placed between theframe arms and the pontoon to distribute the weight of the frame on thepontoon. The walls of the hot tub are made from a thermally insulatingmaterial such as neoprene rubber. The insulating material helps to keepthe water in the tub from losing heat too rapidly to the external bodyof water. When the hot that is filled with water, the majority of thetub is submerged below the surface of the external body of water,providing stability. The hot tub is designed such that when filled withwater, the water level inside the tub is approximately the same level asthe external body of water.

In accordance with one aspect of the invention, a portable floating hottub comprises a collapsible frame of connected rigid members having acollapsed configuration and a deployed configuration. The deployed frameforms an interior volume, at least one seat for a person within thevolume, and an upper periphery. An insulated liner is sized and shapedto fit closely against and attach to the deployed frame to form asubassembly and define a hot tub fill volume within the liner. Aninflatable pontoon buoyantly supports the deployed frame and linersubassembly. Cooperating means on the collapsible frame, the insulatedliner, and/or the inflatable pontoon couples the frame and linersubassembly to the pontoon. The inflated pontoon has sufficient buoyancyto support the frame and liner subassembly in a body of water with theupper periphery of the frame above the water level. Finally, a source ofhot water connects to circulate water to and from the hot tub fillvolume.

In one embodiment, the cooperating means comprises at least one lateralextension from the frame and liner subassembly that engages the pontoon.For instance, the cooperating means may be flexible straps. The sourceof hot water desirably comprises a hand-carried portable heater havingan inlet and an outlet and hoses connected therewith for circulatingwater to and from the hot tub fill volume. A preferred insulated linercomprises a foam core and protective outer layers, and is easilyseparable from the frame. In one form the collapsible frame comprises aplurality of lightweight rigid struts connected at junctions. Forautonomous navigation of the hot tub a small motor may be mounted on thepontoon. Advantageously, the inflatable pontoon has a closed geometricform surrounding a central aperture within which the deployed frame andliner subassembly are peripherally supported.

Another portable floating hot tub of the invention comprises acollapsible frame of connected rigid members having a collapsedconfiguration and a deployed configuration, wherein the deployed frameforms an interior volume, at least one seat for a person within thevolume, and an upper periphery. An insulated liner is sized and shapedto fit closely against and attach to the deployed frame to form asubassembly and define a hot tub fill volume within the liner. A pontoonbuoyantly supports the deployed frame and liner subassembly such thatthe upper periphery of the frame is above the water level. Ahand-carried portable heater having an inlet and an outlet and hosesconnected therewith circulates water to and from the hot tub fillvolume. The heater has a tilt sensor that shuts off operation of theheater if the heater tilts more than a predetermined amount from anupright orientation. Cooperating means may be provided on thecollapsible frame, the insulated liner, and/or the pontoon for buoyantlycoupling the frame and liner subassembly to the pontoon. The collapsibleframe desirably comprises a plurality of rigid struts hinged together.The heater may have a gas burner and an electric control therefore, anda heating capacity of at least 30,000 BTUs. Another element of thesystem may be a submergible water pump having an inlet and an outletwith an outlet hose connected to the inlet of the heater. The pontoondesirably has at least one inflatable bladder that is capable of beingcollapsed and hand-carried in a bag.

A still further embodiment of a portable floating hot tub comprises acollapsible frame, an insulated liner attached to the deployed frame toform a subassembly, and an inflatable pontoon arranged to buoyantlysupport the deployed frame and liner subassembly. A hand-carriedportable heater is provided to circulate water to and from the hot tubfill volume, and the hot tub components can be collapsed and stored inone or more carry bags with a combined weight of less than 100 pounds.Preferably, the collapsible frame comprises a plurality of lightweightrigid struts connected at junctions, some of which are dedicated hingesand some of which are detachable. The inflatable pontoon may have aclosed geometric form surrounding a central aperture within which thedeployed frame and liner subassembly are peripherally supported.Desirably the insulated liner is easily separable from the frame, andmore particularly the insulated liner has a plurality of tabs securedthereto for attaching the liner to the deployed frame.

A method for rapidly deploying a floating hot tub of the presentinvention includes deploying a collapsible frame of connected rigidmembers having a collapsed configuration and a deployed configuration,wherein the deployed frame forms an interior volume, at least one seatfor a person within the volume, and an upper periphery. An insulatedliner sized and shaped to fit closely against and attach to the deployedframe is provided, and the deployed frame and the liner are coupled toform a subassembly and define a hot tub fill volume within the liner. Aninflatable pontoon arranged to buoyantly support the deployed frame andliner subassembly is inflated placed it in a body of water. The userfills the hot tub fill volume with water so that the upper periphery ofthe frame is buoyantly supported by the pontoon above the water level,and then circulates heated water to the hot tub fill volume.

The pontoon preferably defines a central aperture and the step offilling causes the frame and liner subassembly to descend through theaperture. Furthermore, cooperating means may be provided on thecollapsible frame, the insulated liner, and/or the inflatable pontoonthat prevent the subassembly from passing completely through the centralaperture. For instance, the cooperating means may be at least onelateral extension from the frame and liner subassembly that engages thepontoon. Desirably, the source of heated water comprises a hand-carriedportable heater having an inlet and an outlet and hoses connectedtherewith for circulating water to and from the hot tub fill volume. Thecollapsible frame may be a plurality of lightweight rigid strutsconnected at junctions, and the step of deploying the frame comprisesunfolding the rigid struts and securing at least one junction tomaintain the deployed configuration. Further, the step of coupling thedeployed frame and the liner preferably involves inverting the frame,draping the insulated liner over the frame, righting the frame andliner, and coupling an upper edge of the liner to the upper periphery ofthe frame. The insulated liner may have a plurality of tabs securedthereto for attaching the liner to the deployed frame.

Another method for deploying a floating hot tub embodied herein,comprises deploying a collapsible frame and coupling an insulated linerthereto to form a subassembly. A user places a pontoon in a body ofwater, positions the frame and liner subassembly adjacent the pontoon,and fills the hot tub fill volume with water so that the frame and linersubassembly descend until the upper periphery of the frame is buoyantlysupported by the pontoon above the water level. Heated water iscirculated to the hot tub fill volume, and the floating hot tub isdetached from any mooring in the body of water and a means of propulsionis used to return to the original or another mooring. Desirably, themeans for propulsion comprises a small motor mounted on the pontoon. Inone embodiment, the pontoon comprises at least one inflatable bladder,and the method includes inflating the bladder. The pontoon may have aclosed geometric form surrounding a central aperture within which theframe and liner subassembly is peripherally supported. In the latterinstance, the step of filling causes the frame and liner subassembly todescend through the aperture, and cooperating means are provided on thecollapsible frame, the insulated liner, and/or the pontoon that preventthe subassembly from passing completely through the central aperture.

A still further method for rapidly deploying a floating hot tub,comprises:

-   -   a. deploying a collapsible frame of connected rigid members,        wherein the deployed frame forms an interior volume, at least        one seat for a person within the volume, and an upper periphery;    -   b. coupling an insulated liner to the deployed frame to form a        subassembly and define a hot tub fill volume within the liner;    -   c. inflating a pontoon;    -   d. placing the inflated pontoon in a body of water of ambient        temperature;    -   e. positioning the deployed frame and liner subassembly adjacent        to the pontoon;    -   f. filling the hot tub fill volume with ambient temperature        water so that frame and liner subassembly descends until the        upper periphery of the frame is buoyantly supported by the        pontoon aperture above the water level;    -   g. circulating heated water to the hot tub fill volume to heat        the water to at least 100° F.; and    -   h. performing the preceding steps in about an hour.

The pontoon may define a central aperture, such that the step of fillingcauses the frame and liner subassembly to descend through the aperture,wherein cooperating means are provided on the collapsible frame, theinsulated liner, and/or the inflatable pontoon that prevent thesubassembly from passing completely through the central aperture. Thesource of heated water preferably comprises a hand-carried portableheater having an inlet and an outlet and hoses connected therewith forcirculating water to and from the hot tub fill volume, the heater havinga gas burner and an electric control therefore, and a heating capacityof at least 30,000 BTUs. The collapsible frame may be a plurality oflightweight rigid struts connected at junctions, and the step ofdeploying the frame comprises unfolding the rigid struts and securing atleast one junction to maintain the deployed configuration. The step ofcoupling the deployed frame and the liner desirably comprises invertingthe frame, draping the insulated liner over the frame, righting theframe and liner, and coupling an upper edge of the liner to the upperperiphery of the frame. The insulated liner may have a plurality of tabssecured thereto for attaching the liner to the deployed frame. All ofthe aforementioned steps may be performed by a single person.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present invention will become appreciatedas the same become better understood with reference to thespecification, claims, and appended drawings wherein:

FIG. 1 is a perspective view of an exemplary portable floating hot tubof the present invention deployed off the back of a boat, andillustrating a portable heater having hoses connected thereto forcirculating hot water to an inner volume of the hot tub;

FIG. 2 schematically illustrates an exemplary rigid frame and insulatedliner in a deployed configuration, prior to filling an inner volume withwater, and positioned within a central aperture of a buoyant pontoon ona body of water;

FIG. 3 schematically illustrates the rigid frame and insulated linerafter having an inner volume filled with water such that the assemblydescends within the central aperture of the pontoon;

FIG. 4 is a perspective view of an exemplary rigid frame of the presentinvention in a deployed configuration;

FIG. 5 is a perspective view of the rigid frame of FIG. 4 in a collapsedconfiguration;

FIG. 6 is a perspective view of the deployed frame above an insulatedliner representative of one step in an assembly process of the floatinghot tub;

FIG. 7 is a perspective view of the assembled frame and insulated linerabove an inflated pontoon representative of another step in the assemblyprocess of the floating hot tub;

FIG. 8 is a sectional view through a portion of a wall of an exemplaryinsulated liner of the present invention;

FIG. 9 is a schematic diagram of an exemplary portable heater used torapidly heat water within the floating hot tub of the present invention;and

FIG. 10A illustrates an alternative version of an exemplary portablefloating hot tub in a rolled-up configuration;

FIG. 10B is an elevational view of the portable floating hot tub of FIG.10A partly deployed;

FIG. 10C shows the portable floating hot tub of FIG. 10B fully deployed;

FIG. 10D shows the deployed hot tub of FIG. 10C floating in an externalbody of water;

FIG. 11 is an alternative version of a portable hot tub similar to thatof FIG. 10C but adapted for placement on land;

FIG. 12A is an exemplary version of a portable floating hot tubillustrating flexible members or straps attached to an upper pontoon andsupporting a floor of an insulated liner;

FIG. 12B is an alternative embodiment of a portable floating hot tubsimilar to that in FIG. 12A and having seats formed therein;

FIGS. 13A-13D are several views of an exemplary portable floating hottub similar to that of FIG. 12A and shown in various stages of collapse;and

FIGS. 14A-14D are several views of the exemplary portable floating hottub of FIGS. 13A-13D shown in various stages of deployment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a portable floating hot tub that is animprovement over previous designs. The exemplary hot tub of the presentinvention is easy to set up and take down by one person in any confinedspace and in a short amount of time, is stable in even choppy waters,and retains heat for a significant length of time. Moreover, thecomponents of the hot tub can be carried in two small luggage-sized bagsthat are easily transported and stored in a small space. A number ofdesirable features described herein combine to provide a truly advancedportable floating hot tub, though it should be understood that certainfeatures by themselves and some combinations thereof are believed noveland may be incorporated into other portable floating hot tubs for asimilar advantage. Therefore, the present invention should not beconsidered limited to the exemplary system described herein, but insteadshould be evaluated by reference to the appended claims.

The 1 illustrates an exemplary floating hot tub 20 of the presentinvention deployed in an external body of water W with a woman enjoyinga soak in a volume V of hot water therein. The hot tub 20 is shownfloating just off the back of a boat B with a portable heater 22supported on a transom platform P thereof. The boat B represents anynumber of solid surfaces from which to deploy the hot tub 20, such asthe edge of the swimming pool, a dock, shoreline, etc. Likewise, thebody of water W represents any number of larger bodies of water,including the ocean, lakes, rivers and ponds, swimming pools, etc.

The present invention is particularly well adapted for deploying off theback of the boat because of its small portable size and minimal spacerequirements for set up. Although the floating hot tub 20 desirablyremains tethered to the boat, its particularly effective insulatingproperties and stability permit it to float freely for some time beforethe inner volume V loses heat. A series of spaced handles 24 around theoutside of the hot tub 20 enhance maneuverability and provide anchoringmembers through which to tether a line. In one particular configuration,the inner volume V is about 250 gallons and the heated water can remainhot for hours, even in the coldest environments.

With reference to FIGS. 1-3, the hot tub 20 comprises three maincomponents: a floating pontoon 30, a rigid frame 32, and an insulatedliner 34 that forms walls dividing the inner volume V from the exteriorbody of water W. The three main components are separable for transportand assembled just prior to deployment in the water W. FIG. 2illustrates the pontoon 30 floating on the water W and a subassembly ofthe frame 32 and liner 34 buoyantly supported by the pontoon. Aprocedure for assembling the hot tub 20 will be described below, inparticular with reference to FIGS. 6 and 7.

As seen in FIG. 1, the pontoon 30 comprises a closed geometric form ofcontinuous air-filled tubular bladders defining a central aperture 40.In the exemplary embodiment the closed geometric form is rectangular.The subassembly of the frame 32 and liner 34 is positioned within thecentral aperture 40 and peripherally supported by the pontoon 30. Ofcourse, those of skill in the art will understand that the principles ofthe present invention described herein are not solely limited to arectangular closed configuration, and other shapes as well as multipleindependent or connected pontoons are contemplated. For instance, onlytwo parallel sides of the illustrated pontoon 30 may be utilized, eitherconnected together with rods or deployed independently and separatelycoupled to the subassembly of the frame 32 and liner 34. The illustratedhot tub 20 provides two comfortable seats for the enjoyment of twopeople at once, as will be explained. Of course, by doubling the widthof the various components a four-person hot tub could be formed.Similarly, a round, hexagonal, or other shaped hot tub could beconstructed based on the principles described herein.

The pontoon 30 may be constructed from one or more bladder unitsinflated with air. That is, the entire rectangular pontoon 30 may beconstructed from a single bladder unit having a common interiorinflation chamber. Alternatively, the pontoon 30 may be constructed of aseries of connected and separate bladder units having separatelyinflated chambers. The latter configuration will provide a measure ofredundancy for safety in case one of the bladder units fails or ispunctured. One useful configuration is to provide at least two inflationchambers separated by one-way valves, yet only a single exteriorinsulation. In such a system, the setup time remains about the same,though leakage from of one of the inflation chambers will not affect theentire pontoon. The bladder units should be large enough to keep outsidewater from entering the hot tub 20, and the pontoon should be largeenough to stabilize the hot tub when people enter or leave directly fromthe surrounding body of water, from a dock, or from the swim platform Pof the boat B. In one exemplary embodiment, the bladders are made of 0.9mm PVC tarp material, and are approximately 1 foot in diameter.

As mentioned above, FIG. 2 illustrates the subassembly of the rigidframe 32 and insulated liner 34 in the central aperture 40 of thepontoon 30. In this configuration, the insulated liner 34 closelysurrounds the deployed frame 32 and defines a hot tub fill volumetherewithin. That is, the walls around the frame 32 formed by theinsulated liner 34 are relatively water-impervious so as to contain thevolume V therein. In FIG. 2, no water has been added to the volume V,while in FIG. 3 water fills the volume V such that the subassembly ofthe frame 32 and liner 34 sinks down through the aperture 40.

The frame 32 possesses at least one, and preferably multiple lateralextensions 50 that engage the pontoon 30 and prevent complete passage ofthe frame 32 and liner 34 subcombination through the central aperture40. In the illustrated embodiment, the lateral extensions 50 compriserigid arms that project outward from the frame 32 at least partly acrossthe radial dimension of the tubular pontoon 30. As seen in FIG. 3, thelateral extensions 50 rest on the top surface of the pontoon 30 and thusprevent the frame 32 and liner 34 subassembly from sinking through thecentral aperture 40. In a preferred embodiment, the operator fills theinner volume V of the hot tub 20 with water to a level that is justbelow the level of the external body of water W, such that when theusers of the hot tub immerse themselves in the hot tub water, the innerand outer water levels are approximately the same. This creates anequilibrium such that the lateral extensions 50 rest lightly on thepontoon 30, and therefore reduces any deleterious effects of excessrubbing and the like. The lateral extensions 50 may also be shaped so asto reduce friction on the pontoon, and in the illustrated embodiment arebent down at their outer ends which helps to prevent injuries to someoneentering or leaving the hot tub.

It should be understood that the illustrated lateral extensions 50 aremerely one configuration for coupling the frame 32 and liner 34subassembly with the pontoon 30. Another configuration is one or moreflexible straps that extend from an upper periphery 52 of the frame 32and attached to rings or other such anchors provided on the upper orouter surface of the pontoon 30. A still further alternative is toextend straps or a web of straps across the pontoon 30 and under theframe 32 and liner 34 subassembly, such as shown in phantom at 54 inFIG. 3. In the latter arrangement, the frame 32 and liner 34 subassemblyare filled with water until they come to rest on the straps 54. Ingeneral, therefore, one or both of the frame/liner subassembly andpontoon 30 includes cooperating means for preventing passage of thesubassembly entirely through the pontoon aperture. Those cooperatingmeans could be rigid arms such as shown at 50 in FIG. 2, or flexiblestraps similarly connected to the frame 32. Alternatively, flexiblestraps could be provided on the liner 34. The cooperating means couldalso be mounted to the pontoon 30, such as the straps shown in phantomat 54 in FIG. 3. If straps connected to the frame 32 or liner 34 areused, they may couple to D-rings or cinches mounted to the pontoon 30,in which case the cooperating means are located on both components.Those of skill in the art will understand that there are numerouspossible configurations of cooperating means, each of which functions toprevent passage, and thus sinking, of the subassembly of the frame 32and liner 34 entirely through the central aperture 40 of the pontoon 30.

FIGS. 4 and 5 illustrate an exemplary collapsible frame 32 for use inthe hot tub 20 of the present invention. FIG. 4 shows the frame 32 in adeployed configuration, while FIG. 5 shows the frame in a collapsedconfiguration. In its deployed configuration, the frame 32 defines asubstantially rectangular upper periphery 52 which, in a preferredembodiment, has a long dimension of about 5 feet and a short dimensionof just under 3 feet. The frame 32 comprises a pair of end sections 64separated by a middle section 66. The middle section 66 is approximatelytwice as deep as the end sections 64 and has a lower floor 68. Each ofthe end sections 64 includes a seat 70. The deployed frame 32 defines avolume therewithin suitable for two adults to sit facing each other onthe seats 70 with their feet resting on the lower floor 68. Although notshown, a small removable step-ladder having hooks for resting on theupper periphery 52 of the frame 32 may be provided to make getting intothe hot tub easier. FIG. 4 shows an alternative to the lateralextensions 50 in that flexible straps 50′ may be used, while FIG. 5shows the rigid extensions 50 as they would be folded in line with thestruts of the frame 32.

In a preferred embodiment, the frame 32 comprises a series of memberssuch as rods or struts 74 made of a rigid lightweight material such asaluminum or fiberglass and connected at junctions 76 that may be hingesor fasteners. Exemplary struts 74 include hollow pipes or rods ofplastic, metal, or composites. Likewise, the lower floor 68 and seats 70are constructed of lightweight panels of nylon or other flexible andstrong material. As seen in FIG. 5, the frame desirably collapses uponitself to a relatively small profile; in the preferred embodiment, thesize of the collapsed frame is approximately 28×28×10 inches indimension, and weighs approximately 40 pounds. To facilitate rapidassembly and disassembly, some of the junctions 76 will be dedicatedhinges (e.g., bolted or riveted), while some will be detachable. Some ofthe hinges may be freely rotating while others are lockable to fix theangle between two connected struts. In one embodiment, the two upperside panels in the middle section 66 completely detach from the rest ofthe frame 32 to facilitate collapse of the remainder of the frame aboutparallel hinge axes. Advantageously, no tools are required to set up ortake down the frame 32. The struts 74 may be secured in their deployedorientations with large thumb screws at the hinged joints, and theresulting deployed frame 32 seen in FIG. 4 is firmly held in its desiredform; that is, in a three-dimensional form defining a volume withinwhich users of the hot tub sit.

FIGS. 6 and 7 schematically illustrate two of the steps in assemblingthe main components of the hot tub 20. FIG. 6 shows the deployed frame32 above the insulated liner 34. The liner 34 is formed of the number ofpanels connected together so as to closely minor the exterior shape ofthe deployed frame 32. Of course, the liner 34 is desirably formed of aflexible material such as NEOPRENE rubber, and only assumes the shapeshown in FIG. 6 once draped around the deployed frame 32. An upper edge78 of the liner 34 defines an opening through which the deployed framepasses. Because of the relative lack of form of the fabric-like liner34, a preferred method of assembly is to invert the deployed frame 32and pull the liner 34 down around it. In this respect, the lightweightnature of these two components facilitate their assembly in that oneperson can invert the frame 32, cover it with the liner 34, and invertthe assembly 80. In an alternative arrangement, the insulated liner 34is sized to fit closely within the deployed frame 32, rather thansurrounding it. In either arrangement, the insulated liner 34 fitsclosely against the deployed frame 32, and may include a series offasteners or hook and loop straps to secure the walls and floor of theliner against the frame, not just the upper periphery.

Subsequently, the frame 32 and liner 34 subassembly 80, seen in FIG. 7,inserts through the central aperture 40 of the pontoon 30. Desirably,the pontoon 30 has first been inflated and placed in the body of waterin which the hot tub 20 will float.

FIG. 8 is a sectional view through a portion of the insulated liner 34.A number of materials having good insulating properties may be utilized,but preferably the liner 34 has an insulating core 81 made of aflexible, preferably foam, material such as NEOPRENE rubber. Aprotective internal barrier 82 and a protective external coating 84sandwich the insulating core 81. The protective barrier 82 and coating84 help prevent damage from sharp objects, and may be coated to helpresist the growth of algae or barnacles. The insulated liner 34 may bemade similar to standard wetsuit material, with an inner foam layersandwiched by outer layers of polymer stretchy fabric. In oneconfiguration, the hollow spaces in the foam liner are filled withnitrogen for its insulation value, as is typical in diving and exposureprotection applications. This also makes the material quite buoyant,which supplements the buoyancy of the pontoon 30. Liners 34 forextremely cold water protection may be made of 7 mm thick NEOPRENE.

FIGS. 6 and 7 also illustrate an exemplary arrangement for coupling theframe 32 and liner 34. In particular, the liner 34 includes a pluralityof pairs of tabs 86 spaced around and extending from its upper edge 78.Each pair of tabs 86 is sized to pass around one of the struts 74 of theframe 32 and couples to each other. The mating tabs may be coupled usinghook and loop fasteners, snaps, or the like. In this regard, the processof assembling the liner 34 to the frame 32 is easy and quick, and can bereversed with the same speed.

With reference again to FIG. 1, the exemplary hot tub 20, once deployed,is filled with water from a source such as a hose, or from thesurrounding body of water W utilizing a submergible pump 88. In thisregard, submergible pump 88 can also be used to empty the hot tub 20when it is time to disassemble the device.

As mentioned above, the portable heater 22 preferably includes a controland monitoring panel 90 and inlet and outlets 92 to which circulatoryhoses 94 connect. In a preferred embodiment, the heater uses liquidpropane (LP) gas, has a 12 V, 40 W power usage, and an output of 88,000BTUs. The heater may be powered by a 12 V power source such as acigarette outlet, or an optional 12 V battery. One particularly usefulembodiment is to use a 36 V rechargeable wheelchair battery. An internalpump circulates water two and from the hot tub volume V through thehoses 94. The preferred heater 22 can heat 250 gallons of water from 60°F. to 105° F. in about one hour.

FIG. 9 is a schematic diagram of preferred elements of the portableheater 22. Desirably, a portable gas heater is used that requiresminimal electric power, is relatively small in size, and simple toinstall or couple to the portable hot tub 20. The water heater shouldinclude safety features such as a tilt shut-off switch, a flow switch,and a thermal shut-off switch. Desirably, the heat exchanger is acontinuous-flow type made from thermally conductive material such ascopper. Other materials may be used if the heater is used extensively incorrosive environments, such as in proximity to saltwater. The burnertypically uses natural or LP gas and should have a heating capacity of30,000 BTUs or greater.

In the embodiment illustrated in FIG. 9, a microcontroller receivesinput from the control panel 90 and various sensors, such as a flametemperature monitor, an exit water temperature monitor, and a hot tubwater temperature monitor. Additionally, the portable heater 22desirably includes a tilt switch connected to shut off the burner andpump if the housing of the heater tips a predetermined amount fromupright. The tilt switch is extremely important for the presentapplication, as the portable heater 22 may be placed in a boat wheremalfunction from tipping over and potential fire are extremelydangerous. The microcontroller is provided with a reset switch functionthat enables the heater 22 to be restarted shortly after being placedupright.

The microcontroller measures the temperature in the hot tub water with athermocouple or thermistor, temperature T3. If the water temperature istoo low, the microcontroller turns on the pump and ignites the burner.Once the desired temperature is reached, the microcontroller turns offthe burner and then the pump. The microcontroller communicates to aburner controller which starts the burner. When switch on, the burnercontroller outputs a high-voltage pulse train to a piezo-igniter (P),opens the gas solenoid, and monitors a burner thermocouple output (T1).After the gas ignites, and the burner thermocouple is hot, the burnercontroller shuts off the piezo-igniter. If at any point the flamethermocouple (T1) or temperature out thermocouple (T2) is not hot, thegas solenoid shuts off immediately, thus turning of the gas burner.Optionally, the functions of the gas solenoid, thermocouple monitoring,etc., can be incorporated into the microcontroller.

The water pump associated with the portable heater 22 desirably usesminimal power, and may be submerged in water or not. Built pumpscommonly used for boats can be used, but have very low power. Such pumpsare capable of producing large flow rates with little water pressure.

The battery or power source used for driving the pump and themicrocontroller may be integrated with the heater, which can be providedwith an internal battery or a power lead for attaching to a 12 V outlet.Typically, the voltage of the pump within the heater is 12 V, and thecurrent draw is less than 10 A.

The present invention enables extremely quick setup and takedown of theportable hot tub 20. First of all, the components of the hot tub 20,including everything shown in FIG. 1, can be collapsed and stored in oneor more carry bags with a combined weight of less than 100 pounds.Desirably, the system components fit into one or more, and preferablytwo small luggage-sized bags that are easily transported and stored in asmall space. In a preferred embodiment, the components of the system arecollapsed and stored/transported in at least two bags to reduce theweight of each bag to less than 50 pounds. A frame bag that holds thepontoon 30, frame 32, and insulated liner 34, measures 28×28×10 inches,and weighs about 40 pounds full. A heater bag measures 24×24×9 inches,and weighs about 30 pounds full. The entire volume of the disassembledsystem is 9 ft³ or less. The only other components are a small 12Vblower, a bottle of LP gas, and an optional 12 V battery.

Setting the hot tub up occurs in the following steps:

-   -   a) Inflate the support pontoon 30—The pontoon may be adapted for        manual inflation, but typically includes a valve that receives a        nipple of a small 12V electric blower, commonly used with        inflatable rafts, chairs, etc. The time required to deploy and        inflate the pontoon 30 is under five minutes.    -   b) Construct the frame 32—Time required to deploy the frame 32        from its collapsed configuration is between 5-10 minutes,        depending on the familiarity and dexterity of the person doing        the work. Quick-connect joints such as spring-loaded pins        greatly facilitate the process. Once finished, the frame 32 is        inverted onto its upper periphery 52.    -   c) Place the insulating liner 34 over the frame—As mentioned        above, the liner 34 closely surrounds the frame 32 and then the        subassembly is turned right side up so as to join all of the        pairs of tabs 86 around the upper periphery 52 of the frame.    -   d) Set the frame/insulating material in the support pontoon—This        step can be seen in FIG. 3, and takes mere seconds because of        the lightweight nature of the frame 32 and liner 34 subassembly        80.    -   e) Fill the tub with water—The time required to fill the inner        volume V of the hot tub 20 depends on the capacity of the pump        used, but typically a small submergible pump such as the one        shown at 88 in FIG. 1 can fill the hot tub 20 in under 10        minutes. As the tub is filled with water the frame and liner        subassembly 80 will sink into the body of water and through the        central aperture 40 of the pontoon 30.    -   d) Heat the hot tub water—The preferred portable heater 22        described above can circulate water at 1-5, preferably 3,        gallons per minute, and can heat 250 gallons from 60° F. to        105° F. in about 45 minutes.

The total setup operation from components being in the carry bags to thehot tub 20 floating and filled with hot water can be accomplished inless than two hours, and preferably in about one hour. That is, thesetup time for the pontoon 30, frame 32 and liner 34 is between 10-20minutes, and filling and heating the water takes between 50-70 minutes.

The process for taking down the hot tub 20 involves first pumping thewater out from the internal volume V, which can be done with thesubmersible pump 88. As the water is pumped out, the frame and linersubassembly 80 will rise relative to the pontoon 30. Once thesubassembly 80 has been substantially emptied, it can be separated fromthe pontoon 30 and inverted to completely empty it. Desirably, the liner34 can be easily separated from the frame 32, such as by coupling thetwo elements with the hook and loop tabs 86. The user lifts the liner 34off of the frame 32, inverts the frame, and collapses or otherwise foldsboth elements and stores them in carry bags. The pontoon 30 preferablyhas a port that can be opened wide for rapid deflation, and it is alsofolded and stored. The portable heater 22, submersible pump 88, and anyother ancillary equipment are placed in their carry bag, which istypically separate from the frame, liner and pontoon. Providing two bagsof 30-40 pounds in weight each is preferable than a single heavier bag.The entire disassembly process may take 20-30 minutes.

Although the preferred embodiment includes separate frame 32 and liner34 elements that the user assembles at the time of deployment, thesubassembly 80 shown in FIG. 7 may alternatively be provided as a singlecollapsible/expandable unit. The advantage of separate parts is thatthey can be collapsed into a smaller aggregate volume, facilitatingtransport and storage. On the other hand, a single unit can conceivablybe designed for easier and faster deployment. Segments of the liner 34may be pre-attached to corresponding frame struts 74 with straps,grommets, stitches, glue, etc.

It should be noted that hot water to fill the hot tub 20 can come fromsources other than the portable gas-powered heater 22. For example, hotwater from a boat motor or other hot water reservoir may be utilized.Alternatively, a solar heat exchange system which is relatively slowerbut more efficient may be used. Also, other portable heaters than theone described above, such as one that uses electric heating elements,can be substituted.

In the case of an “independent” hot water system, such as a solarheater, the heater may be supported on the pontoons that are used tofloat the hot tub. Alternatively the heating system may be placed on asmall independent pontoon.

Moreover, in certain circumstances the portable floating hot tub 20 maybe used to provide cooler water than the surrounding ambient body ofwater, such as in a mid-summer tropical environment. In thatconfiguration, a water cooler rather than a heater is used.

The floating hot tub 20 described herein provides substantial structuralintegrity, as opposed to other commercial designs that are relativelyflimsy. Because of the rigid internal frame 32, the overall shape of thehot tub 20 is maintained even in the presence of large external forces.The relatively large pontoon 30 helps to cushion the hot tub 20 in caseof a collision with a boat or other objects, and the internal frame 32prevents the shape from distorting. Moreover, the large pontoon 30provides a relatively high barrier to keep cold water from entering thehot tub when there is turbulent or choppy water.

It is often enjoyable to float in the hot tub 20 a large distance fromthe boat or stock. In this case, a long line may be attached to the hottub tether it to the boat or dock. Before floating away from the boat,the hoses 94 connecting the portable heater 22 from the internal volumeV are removed. Alternatively, a separate pontoon for the heater unit 22and an LP gas cylinder and battery pack can be floated next to the hottub 20. More ambitiously, the hot tub 20 can be made autonomous fromland or a boat by providing it with a small motor, such as a smallelectric outboard motor of 5 to 80 horsepower (4 to 60 kW), as shown inphantom in FIG. 1). Any means of propulsion may be supplied, includingthe aforementioned motor, oars, a double-ended paddle, even a smallsail. Consistent with the principle that the hot tub 20 can be formed ina number of shapes, the exterior contours can be streamlined to resemblea small dinghy or Zodiac-style inflatable boat so as to facilitate tripsaround a harbor, for instance. The presence of the rigid frame 32greatly enhances the ability for propulsion through the water as itsupports the overall form of the hot tub. The relatively large pontoon30, preferably about 1 foot in diameter, also helps make the hot tub 20seaworthy, as it provides a relatively high barrier to waves splashingover the edge and into the internal volume V.

It is also conceivable that certain inventive principles of the hot tub20 described herein may advantageously be incorporated into a somewhatless portable structure. For example, the highly portable collapsiblerigid frame and insulated liner may be deployed and placed with asomewhat less portable pontoon structure, such as a Zodiac-styleinflatable boat. In other words, a Zodiac-style or other small boathaving a relatively large central aperture may remain in the water, suchas in a harbor, but the other components of the portable hot tub 20 arestored on land and only deployed when needed. In this configuration, theconstruction of the pontoon can be significantly more robust, as well asproviding a rugged mount for a larger motor, thus improving the abilityto transit distances across open water. In this regard, therefore, theterm “pontoon” encompasses both a simple bladder structure collapsibleinto a bag that can be hand-carried, as well as a more permanentstructure such as defined above. With such as system, all the componentsbut the pontoon remain extremely portable.

Furthermore, the insulated liner 34 provides excellent heat retentionfor the hot tub 20, even in water as cold as 32°. In a preferredembodiment, the insulated liner 34 has the capacity to lose only 1° F.of temperature of hot water (e.g., 105° F.) within the internal volume Vevery 20 minutes to surrounding water of 60° F. or less. The thicknessof the insulating layer can be increased depending on the temperature ofthe surrounding environment, with a trade-off being a correspondingincrease in weight and decreased portability. Also, a cover (not shown)over the top of the hot tub 20 may be provided to better retain heatwhen the hot tub is not in use.

One very useful option for the system shown in FIG. 1 is to provide arod-like extension from the lower end of the portal heater 22 so that itcan be mounted in a fishing rod holder off the back of the boat. Such anextension can be rigidly connected to the housing of heater 22, or aseparate basket-like frame with the extension can be provided. In thisway, the heater 22 is securely held in an upright position close to thehot tub 20.

As mentioned above, one configuration for the portable floating hot tubof the present application is to position the insulated liner within theframe. Moreover, the frame may be modified to facilitate collapse, asmentioned above. One advantageous arrangement that permits the hot tubto be collapsed by rolling it up into a compact configuration is toeliminate all but the floor of the frame, and to form the floor so thatit can be rolled up with the liner. For instance, a continuous ribbed ordiscontinuous slatted floor could be rolled up while providingstructural rigidity to the floor. Instead of providing rigid struts forthe sidewalls of the frame, flexible straps or members can be suspendedfrom the pontoon to support the floor. By positioning the floorunderneath the liner, the liner can thus be suspended by the flexiblestraps. FIGS. 10-14 illustrate this alternative embodiment. It should beunderstood that various components described above may be incorporatedinto the versions shown in FIGS. 10-14, such as the portable heater thatis not illustrated for brevity. Likewise, elements shown and describedwith respect to FIGS. 10-14 may be combined with certain features above,and the range of possible combinations of individual features should notbe considered limited by any one exemplary combination.

FIGS. 10A-10C illustrate an exemplary portable floating hot tub 100 inrolled-up, partly deployed, and fully deployed configurations,respectively, while FIG. 10D shows the deployed hot tub 100 floating inan external body of water. The hot tub 100 comprises an inflatablepontoon 102 arranged around a central aperture (not shown in theelevational views) to which is secured an upper periphery of aninsulated flexible liner 104. The flexible liner 104 has athree-dimensional shape to be filled with water and extend downwardwithin the central aperture and define a hot tub fill volume, much likethe earlier embodiments. A plurality of rigid members 106 provided onthe bottom of the three-dimensional shape of the flexible liner have adeployed configuration shown in FIGS. 10B-10D that forms a floor underthe liner 104. Although not shown, the rigid members 106 are capable ofbeing converted into a collapsed configuration, such as the rolled-upshape in FIG. 10A to facilitate portability.

In this version, only the side walls of the liner 104 support the floorthereof as it is suspended below the pontoon 102. Given that there iswater within and surrounding the filled liner 104, the weight pulling itdown is fairly small without people being in the tub. The walls of theliner 104 may be formed with reinforcing strands or fibers to preventtearing. Alternatively, a more sturdy external suspension system such aslines described below may be used. Likewise, though rigid members 106such as slats may be incorporated into the floor of the liner 104, thebottom may instead be reinforced by thickening the material, or withspars or elements similar to battens in sailboat sails for lightweightrigidity.

The insulated liner 104 attaches around the central aperture of thepontoon 102 in a substantially continuous interface. By that is meantthat the upper periphery of the liner 104 defines a closed shape, suchas a circle, square, rectangle, etc., that generally conforms to theshape of the pontoon 102, and is substantially continuously connectedtherewith so that no large gaps are present. In a preferred embodiment,the upper periphery of the liner 104 is bonded continuously to the inneredge of the pontoon 102, or it passes up through the inside of thepontoon 102 and bonds to the upper surface. One means for bonding is toheat seal the upper periphery of liner 104 to the inner surface of thepontoon 102, although an epoxy or other such adhesive that will holdupon submersion in water may be utilized. Alternatively, the liner 104may be removably coupled to the pontoon 102, such as with the use ofzippers, a series of closely-spaced snaps, Velcro, straps and doubleD-rings, etc. The unitary nature of a more permanent connection, such asheat sealing, is preferable for simplicity, though a detachable couplingfacilitates replacement of just one of the two components.

FIG. 11 illustrates a land version of a portable hot tub 120 similar tothat of FIG. 10C in that it includes an inflatable upper rim 122, andinsulated liner 124 and a plurality of rigid members 126 positioned atthe bottom of the liner. Indeed, the hot tub 120 may be identical to thehot tub 100 described above. In addition, however, the upper rim 122rests on an inflatable collar 128. In the illustrated embodiment, theinflatable collar 128 includes a pair of stacked inflatable rings. Theinflatable collar 128 may be provided as an option with the floating hottub 100 to convert it to the portable hot tub 120 for use on land.

FIG. 12A schematically illustrates a liner suspension system for aportable floating hot tub 130. The hot tub 130 may include theaforementioned pontoon 132, with an insulated liner 134 extendingdownward through a central aperture thereof. A plurality of flexiblemembers or straps 136 attach to the pontoon 132 and support a floor ofthe insulated liner 134. Although the insulated liner 134 may beprovided with a thicker bottom for rigidity, a preferred embodimentincludes a plurality of rigid members 138 such as slats or planks. Asmentioned above, the rigid members 138 are desirably aligned in paralleland spaced apart to facilitate rolling the hot tub 130 up into a smallprofile. The slats 138 used in the bottom of the tub should be lessdense than and float when in water. Wood or plastic could be used. Thismakes it so that the bottom of the tub floats up as it is emptied. Theflexible members 136 may be straps, ropes, cables, or any suitableexpedient. The flexible members 136 extend from the pontoon 132 under abottom of the liner 134 to the rigid members 138 such that when thepontoon is floating, the weight of the liner filled with water issupported partly by the flexible members. Further details of thisarrangement will be described below with reference to FIGS. 13-14.

FIG. 12B is a hot tub 140 similar to that in FIG. 12A and having seats142 formed therein. More particularly, a plurality of rigid members 144form the floor of the hot tub volume and are suspended by flexiblemembers 146. On each end of the hot tub 140, stepped areas of the liner148 are supported by rigid members 149 suspended by flexible members150. It should be mentioned here that the hot tubs 100, 120, 130, and140 are not shown in plan view, and could be provided in a variety ofgeometric shapes. Therefore, the hot tub 140 could be formed as ahexagon or other polygon with the seats 142 arranged symmetricallyaround the outside.

FIGS. 13A-13D are several views of an exemplary portable floating hottub 151 similar to that of FIG. 12A and shown in various stages ofcollapse. These views illustrate a plurality of rigid members 152inserted in open-ended pockets 154 formed in the underside of a floor ofa flexible insulated liner 156. The rigid members 152 are slat-like, andinclude rounded outer ends each with an eyehole 158. Lines 160 aresecured to the eyeholes 158 and on the other end to a plurality ofanchors 161 provided to the exterior of inflatable pontoon 162.Preferably, the anchors 161 comprise D-rings that are positioned in anarray around the underside of the pontoon 162. In a preferredembodiment, two lines 160 attach to each slat end and extend upward in aV-shape to different anchors 161 provided on the pontoon 162.

FIG. 13C shows a convenient technique for rolling the hot tub 151. Thatis, two lateral sides that run perpendicular to the direction of therigid slats are folded inward such that the deflated hot tub 151 has awidth about the same as the length of each slat. From there, one end isrolled up as seen in FIG. 13D.

FIGS. 14A-14D are several further views of the portable floating hot tub151 of FIGS. 13A-13D shown in various stages of deployment.Specifically, FIG. 14A shows the hot tub 151 deflated and spread out ona flat surface. In FIG. 14B, a pump (in this case and pump) has beenused to inflate the pontoon 162 while still on land, or otherwise on asolid surface. In FIG. 14C, the hot tub 151 has been lowered into thewater and a water hose 164 drapes through the central aperture 164 forfilling the inner volume of the hot tub. This view shows the floor 168of the insulated liner 156 prior to descending downward below thepontoon 162. Ultimately, the weight of the water causes the floor 168 tosink downward until it reaches the point at which the sidewalls of theliner 156 are taut, which is desirably the same point that thesuspension lines 160 become taut.

FIG. 14D illustrates the hot tub 151 after having been emptied of waterwithin the fill volume, lifted onto a land surface and inverted. Thefloor 168 having the pockets 154 and slats 152 therein is visible. Thisinverted position is relatively simple to accomplish after almost all ofthe water has been pumped out of the fill volume, and permits theremaining water to be drained completely from the fill volume.

The first step in deployment of the hot tub 151 is unrolling theinflatable, the second step is inflating the pontoon. Because theinsulated side walls are flexible, the bottom slats remain close to thepontoon, see FIG. 14B. At this point if the hot tub 151 will be used inwater, it is placed in water, as in FIG. 14C. As the tub fill volume(within the liner 156) is filled with water, the bottom or floor of theliner will sink until the tub is in the fully deployed configuration,see, e.g., FIG. 12A. Alternatively, if the hot tub 151 will be used onland, the pontoon 162 is placed on the inflatable collar 128, which hasa height such that the slats at the bottom of the tub touch the ground.

An advantage of this design is that it can be fabricated in a number ofshapes and sizes. For example, it could be easily fabricated in acircle, a square or even a star configuration. Also, the bottom of thetub could be flat, have seats, or be curved to fit the contour of ahuman body.

Because the tub may be used in colder water and climates, it isessential that the sides of the wall be insulated. The walls could bemade from an insulating material such as neoprene. If the walls of thetub are fabricated from a material such as vinyl, insulation may beachieved by gluing an insulating material such as neoprene to the walls.Alternatively the neoprene could be held to the vinyl walls with snap onclips. An advantage to clipping the insulating material to the walls isthat the thickness of the insulating material could be varied dependingon the location of use. Another option is to place the thermallyinsulating material inside the walls of the spa sandwiched betweenlayers of vinyl, for example.

The materials for the spa may vary. The inflatable pontoon can be madefrom PVC, PVC Tarpaulin, or Hapylon and must be capable of remainingfully inflated for several days. The insulating material presently usedis neoprene. However, if the insulating material is located sandwichedwithin the sealed walls of the spa where it is dry, any insulatingmaterial may be used. For example, a polyester blanket material may beused as the insulating material between outer layers of nylon.

Although the tub could be constructed using only the side walls tosupport the floor, it could be advantageous to add additional supportfor the floor. As an example, ropes between the inflatable and the slatson the floor could support the floor.

Many optional accessories can be added to the tub. For example a ladderthat could be used on the outside of the tub to allow entry to the tubfrom the outside body of water. The same ladder could be used on theinside of the tub to help in exiting the tub. Seats that clip onto theinflatable could be used to make the tub more comfortable. An accessorysafety flag and lights may be added to facilitate others seeing the tubin a body of water. In one deployment, the hot tub can be placed in theback of a pickup truck and moved while filled as a portable land-basedhot tub.

Also, a conductive element between the inside of the tub and outside ofthe tube may be used to equalize the potential between the outside waterand inside water. A rivet or screw could be used. This is especiallyhelpful in marinas.

In cases where many people are using the spa, the water may be filteredwith a traditional spa filter using a circulating pump. Alternatively anozonator or chemicals such as bromine or chlorine may be used to keepthe water clean.

One or more drain plugs could be added to the bottom of the spa. On landthe drain plug could be used to empty the spa. When in the water,opening the plugs would facilitate the exchange of water withoutemptying the tub.

It is often useful to have a removable support for the heater and/orpropane that can be held onto the side of a boat.

The following Table provides exemplary specifications for various modelsof the hot tub described herein:

TABLE I HOT TUB SPECIFICATIONS Two Person - Four Person - Two Personw/seats Four Person w/seats Spa Outside 84″ × 53″ × 28″ 84″ × 53″ × 42″84″ × 62″ × 28″ 84″ × 62″ × 42″ Dimensions Water Capacity 138 Gal. 187Gal. 181 Gal. 245 Gal. People Capacity 2 persons 2-3 persons 3-4 persons4-5 persons Water Heater 88,000 BTU 88,000 BTU 88,000 BTU 88,000 BTUWater Heater 14″ × 18″ × 22″ 14″ × 18″ × 22″ 14″ × 18″ × 22″ 14″ × 18″ ×22″ Dim./Weight 25 Lbs 25 Lbs 25 Lbs 25 Lbs Time to Heat 70 minutes 70minutes 70 minutes 100 minutes (60 to 100 deg) LP Gas to Heat 1 Gal 1Gal 1 Gal 1.5 Gal Water Spa Bag 17″ × 17″ × 34″ 17″ × 17″ × 34″ 17″ ×17″ × 43″ 17″ × 17″ × 43″ Size/Weight 40 lbs 50 lbs 50 lbs 55 lbs HeaterBag 24″ × 22″ × 11″ 24″ × 22″ × 11″ 24″ × 22″ × 11″ 24″ × 22″ × 11″Size/Weight 35 lbs 35 lbs 35 lbs 35 lbs Safety Features Tilt Sensor TiltSensor Tilt Sensor Tilt Sensor Two over temp. Two over temp. Two overtemp. Two over temp. sensors sensors sensors sensors Flow Sensor FlowSensor Flow Sensor Flow Sensor Supported Supported Supported Supportedslatted floor slatted floor slatted floor slatted floor Electric Power12 V, 3 Amps, 12 V, 3 Amps, 12 V, 3 Amps, 12 V, 3 Amps, 36 Watts 36Watts 36 Watts 36 Watts

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the present disclosurehas been made only by way of example, and that numerous changes in thecombination and arrangement of parts can be resorted to by those skilledin the art without departing from the scope of the invention, ashereinafter claimed.

1. A portable hot tub, comprising: an inflatable pontoon arranged arounda central aperture; an insulated flexible liner having an upperperiphery secured to the pontoon around the central aperture and havinga three-dimensional shape to extend downward within the central apertureand form a hot tub fill volume; flexible members that extend from thepontoon to support a bottom of the liner such that when the pontoon isfloating, the weight of the liner filled with water is supported partlyby the flexible members; a hand-carried portable heater having an inletand an outlet and hoses connected therewith for circulating water to andfrom the hot tub fill volume.
 2. The hot tub of claim 1, furtherincluding a floor of a more rigid material than the flexible linerincorporated within a bottom surface of the liner and attached to thepontoon via the flexible members.
 3. The hot tub of claim 2, wherein thefloor comprises at least one lightweight panel of a flexible and strongmaterial.
 4. The hot tub of claim 2, wherein the floor comprises aplurality of slats spaced apart and oriented in parallel such that thefloor can be rolled up about an axis parallel to the slats.
 5. The hottub of claim 2, wherein the flexible members attach to anchors providedon the pontoon.
 6. The hot tub of claim 1, wherein the upper peripheryof the flexible liner is secured to the pontoon with a plurality offlexible members.
 7. The hot tub of claim 1, wherein the upper peripheryof the flexible liner is secured to the pontoon along a substantiallycontinuous interface.
 8. The hot tub of claim 1, wherein the heater hasa tilt sensor that shuts off operation of the heater if the heater tiltsmore than a predetermined amount from an upright orientation.
 9. Afloating portable hot tub, comprising: an inflatable pontoon arrangedaround a central aperture; an insulated flexible liner having an upperperiphery secured to the pontoon around the central aperture and havinga three-dimensional shape to extend downward within the central apertureand define a hot tub fill volume; a plurality of rigid membersincorporated in the bottom of the three-dimensional shape defined by theflexible liner, the rigid members having a deployed configurationdefining at least a floor under the liner and a collapsed configurationto facilitate portability; and a plurality of flexible members extendingdownward from the pontoon to support the bottom of the flexible linerand rigid members such that when the pontoon is floating in a body ofwater and the hot tub fill volume is filled with water the weight of theliner filled with water and any occupants of the hot tub is supportedpartly by the rigid members.
 10. The hot tub of claim 9, furthercomprising a hand-carried portable heater having an inlet and an outletand hoses connected therewith for circulating water to and from the hottub fill volume.
 11. The hot tub of claim 9, wherein the plurality ofrigid members defines part of a three-dimensional frame that attachesaround the exterior of the liner.
 12. The hot tub of claim 9, whereinthe floor comprises a plurality of slats spaced apart and oriented inparallel such that the floor can be rolled up about an axis parallel tothe slats.
 13. The hot tub of claim 9, wherein the upper periphery ofthe flexible liner is secured to the pontoon with a plurality offlexible straps.
 14. The hot tub of claim 9, wherein the upper peripheryof the flexible liner is secured to the pontoon along a substantiallycontinuous interface.
 15. The hot tub of claim 9, wherein the flexiblemembers attach to anchors provided on the pontoon.
 16. A floatingportable hot tub, comprising: an inflatable pontoon arranged around acentral aperture; an insulated flexible liner having an upper peripherysecured to the pontoon around the central aperture and having athree-dimensional shape to extend downward within the central apertureand define a hot tub fill volume; a plurality of slats spaced apart andoriented in parallel into a bottom of the three-dimensional shapedefined by the flexible liner, the slats having a deployed configurationforming a reinforced floor of the liner and a collapsed configurationwherein the slats are rolled up about an axis parallel to the slats tofacilitate portability; a plurality of flexible members extending fromthe pontoon to attach to the slats such that when the pontoon isfloating in a body of water and the hot tub fill volume is filled withwater the weight of the liner filled with water is supported partly bythe slats; and a hand-carried portable heater for circulating water toand from the fill volume.
 17. The hot tub of claim 16, wherein the upperperiphery of the flexible liner is secured to the pontoon along asubstantially continuous interface.
 18. The hot tub of claim 16, furtherincluding open-ended pockets formed in an underside of the liner intowhich the plurality of slats fits.
 19. The hot tub of claim 18, whereineach slat has at least one flexible member attached to both endsthereof.
 20. The hot tub of claim 19, wherein there are two flexiblemembers attached to each slat end and extending upward in a V-shape todifferent anchors provided on the pontoon.